Well water contains many contaminants. If not removed from the water, these contaminants may present health risks, may damage plumbing and personal property and may adversely affect the taste of the water. The prinicpal contaminants naturally occurring in well water are iron, sulphur and manganese. Many man-made contaminants are also now found in well water. These man-made contaminants, generically defined as halogenated organics, may be introduced into the water supply as part of or as by-products of herbicides, pesticides, fertilizers and the like placed on and into the ground. These halogenated organics are believed to be carcenogenic and may present serious long term health risks to users of this contaminated water.
Many different systems have been developed in an attempt to remove contaminants from our water supply, be it a central water system or a well system. The three main system types for contaminant removal consist of chlorination, ion exchange and filtration. In the filtration type, the McLean and Patterson water treatment systems for removal of iron contaminants are believed to be the most relevant to the water treatment system of the present invention.
In the McLean system, as shown in McLean U.S. Pat. No. 3,649,532, the well water passes through a venturi type apparatus to entrain air into the water, and this air laden water is then introduced into a filter tank. The venturi apparatus is theoretically controlled to introduce only enough air into the water to cause the iron contained in the water to change into a colloidal form. The air intake is limited so as not to oxidize the iron contained in the water stream. The water with the iron in colloidal form passes into a filter tank and then the filtration bed contained in the filter tank. This filtration bed slowly raises the pH of the water passing therethrough while filtering the iron hydroxide and other impurities therefrom. The Patterson system has an air inlet that must be closely controlled to cause the iron to go into a colloidal state for removal as iron hydroxide.
The Patterson iron removal system includes a micronizer in the water line leading to the filter tank. The micronizer adds air to the water and converts the ferrous and ferric iron into tiny electrically charged particles. The air laden water with the charged iron particles is then passed through a media bed carrying an opposite charge to attract the iron particles. The iron particles then electrostatically cling to the filter media, with the entire media bed depth being utilized for this electrostatic removal of iron particles. The Patterson system requires the micronizer to be carefully set to control the amount of air introduced into the water and requires a specialized media bed preconditioned at the factory to have the opposite charge to the iron particles leaving the micronizer.